The LAPD was recently featured employing their K2 Canine, Nelly, who was trained through out Person-Borne Explosive Detection Dog course. Person-Borne canines can scan up to 150 people per minute, in a crowd, and while moving. Their main goal is to detect explosives on humans while they move through crowds. This technology is perfect for large crowds and public places, such as concerts, sporting events, and mass transit hubs.
K2 is currently the only company who is Department of Homeland Security SAFETY ACT designated for this Person-Borne Explosive Detection Dog Technology; the Science and Technology Designation for Developmental Testing & Evaluation. Here is the video from CBS News: